I always found this very distracting when I was driving.
Ever see the movie, The World According to Garp (1982)? There is a scene in this movie where "automobile" fellatio has disastrous results. Garp's wife was giving oral sex to her student lover when Garp rear ended them. She bit off his penis.
Had a chick try to blow me while driving once... I was driving my buddies 4-Runner... She knocked it out of gear and I put the engine almost to the redline when I got off the gas and knocked it back into gear.
Never ever doing that again. I can wait the 20 minutes to get to the house and if I can't, I'll find a desolate area to pull over and bang her.